水素による溶銅の脱酸反応速度

Abstract

Deoxidation of molten metals by hydrogen is not only used frequently as a deoxidation method in the melting operation on a laboratory scale, but also as an indirect industrial application in the refining of blister copper by ammonia gas. As an example of gas-molten copper reactions, the authors studied the velocity of the deoxidation by hydrogen diluted with argon under various experimental conditions by the use of the resistance furnace. From the experimental results on the diffusion control of hydrogen molecules in the gaseous film and of oxygen atoms in the stagnant molten copper, it was found that the velocity of the deoxidation could not be explained by a simple mechanism. However, it became evident the resistance of diffusion of hydrogen molecules in the gaseous film to the velocity of the deoxidation was very small and molten copper was stirred even in case the resistance furnace was used.It is assumed that the deoxidation of molten copper by hydrogen occurs in a complicated reaction mechanism, because of the following three reasons in addition to the facts described above: (1) the rate of increase of the deoxidation velocity decreases with rising PH2, (2) the reaction plane exists in addition to the free surface, (3) the apparent activation energy of the deoxidation reaction is 12.1 kcal/mol which is thought to be too large as a value of mass transfer.